"A. You know, of course, that she used to dive for her college swim team." does not have any errors in comma usage. "Of course" is almost always surrounded by commas.
Sorry, not sure about all answers but I hope these help:
Task 1
1 fortune
2 precious
3 overpriced
4 credit
5 debt
6 idk
7 profit
8 well off
9 financial and idk
10 priceless